In the past few years, several new synthetic, "designer drugs" have emerged as the new thing. Bath salts are probably the most well-known. Another big one is Spice, or K2, a kind of synthetic marijuana. Spice is potent, and can have intense side effects, but efforts to ban it at both the federal and state levels have proven tricky. And as Samantha Fields reports, in Maine it's still widely accessible and increasingly popular among young people.

Officer Knight has a couple of the packets tacked to the wall next to his desk. They're not innocuous and they're not "potpourri." They're a drug, generally called "Spice" or "K2" - herbs that look like marijuana and have been sprayed with a mix of chemicals to produce a high that's supposed to be similar to marijuana. And they are intended - and marketed - for human consumption.

"Spice has been described as a synthetic marijuana, but it's much more potent than anything you would get in marijuana, it's much more potent than the active ingredient, for example, THC, which is found in marijuana, which makes it a very dangerous and problematic drug," says Dr. David Shurtleff, the acting deputy director for the National Institute on Drug Abuse at the National Institutes of Health.

Shurtleff says what makes Spice so dangerous is that the chemicals in it haven't been tested so no one really knows their effects on the human body. In many cases, the immediate effects are hallucinations, anxiety, heart palpitations, vomiting and disorientation. In a few cases, in other states, Spice has even been linked to deaths.

"I think the most telling sign is the number of calls to poison control centers," Shurtleff says. "For example, in 2011, there were 13,000 calls relating to synthetic Spice."

Sixty percent of those were for patients 25 and under. A national study found that one in nine high school seniors have tried Spice.

Daniella Cameron, a social worker and supervisor at the Preble Street Teen Center in Portland, says it's one of the most common drugs currently being used by teens and young adults, and she's worried about what she's seeing.

"We've had a handful of youth who've had seizures, actually, in our space, who've come in high on Spice, that they've reported to us afterwards that that's what it was that they were on," Cameron says. "But, clearly, kids coming in under the influence and disoriented, unable to maintain a conversation, nodding out."

Cameron says Spice first came on her radar about a year ago, and that its popularity seems to have exploded in the last six months. Stephanie, who's 20 and lives in Portland, says there are a couple reasons it's become so popular among young people.

"Because it's cheap. And it gets you high," she says. "It's cheaper than marijuana, which most of them used to smoke marijuana, and they were better when they did that. But you can get a gram and a half for $10. And you can get a gram of weed for $20."

Tom, who's also 20 and living in Portland, says there's another advantage: "A lot of people on probation smoke it as an alternative to weed because it doesn't show up in urine."

It's also extremely easy to get. And Officer Daniel Knight says the versions that are currently on the market are technically legal. "It is legal. I guess it's just like any smoking material. Anyone of legal age can go in and buy it," Knight says.

That's in spite of efforts at both the federal and state level to make it illegal. The federal government banned Spice in 2011. And by now, at least 41 states - including Maine - have banned some versions of synthetic cannabinoids. Sgt. Kevin Cashman, with the Maine Drug Enforcement Agency, says the problem is that drugmakers have been able to get around bans by slightly altering the chemicals they're using.

"The people that are producing these substances are ahead of the game," Cashman says. "And law enforcement and the legislators both nationally and locally, are playing catch up."

Twenty-year-old Stephanie says she's upset that local head shops and gas stations are still selling Spice, especially after seeing what the drug does to her friends.

"It does something to them - I don't know what it is, but I've seen multiple people fall down and have seizures, they forget everything, and they get addicted to it. They really do," she says. "And I don't understand it. I tell them to stop. I tell everyone I know not to smoke Spice. And it's like a sickness. They have to smoke it. They have withdrawals from it. Physical withdrawals and everything."

One employee at a shop in downtown Portland acknowledged that he sells Spice, but was reluctant to discuss it any further. Stephanie says she's so frustrated by the situation that she's tempted to make herself some signs, and go stand in front of one of the shops in protest.